A bearing seat of a ball joint improved in lubricity is provided. By opening a plurality of dimples that are opened on a spherical sliding surface that rotatably holds an approximately globular ball portion of a ball stud and house a grease, the dimples can be provided in a balanced manner in proximity to each other, therefore, the grease spreads out between the respective dimples even when sway of the ball portion is relatively small, and lubricity can be improved.